Rotary sieve is a cylindrical shaped rotating sieve, with replaceable mesh rolled to the shape of a cylinder. The mesh is set to rotate about a central shaft, which can be operated by hand. The handle can be can be replaced by pulley drive if mechanization is required. The end faces are left open which acts as input and output portals. Helical shaped structure is provided within the sieve, which facilitates the flow or scavenging of materials from one end to the other.
The raw sand feeder or hopper is used for supplying the raw sand into the sieve. It is connected to the base frame near the input portal of the sieve using threaded fasteners, such that it can be removed if not necessary. A chute is connected to the output portal of the sieve to remove the gravel to a convenient distance. It is used to take out the gravel and other waste materials. Chute for collecting fine sand is located at the bottom of the sieve. Polycarbonate dust cover is used to prevent dust spreading to air while sieving dry sand.
180 pans of river sand (1 pan is approximately equivalent to 4.5 kg) can be sieved in an hour which is about three times the conventional sieving, in addition to reduced drudgery of the worker. The rotary sieve can also be used for sieving vermi-compost, potting mixture and other organic manures.